Neutrinos faster than the speed of light? Not so fast ...
REPORTING FROM LOS ANGELES -- Faster-than-light neutrinos, we hardly knew ye.
Back in September, a group of physicists working at the OPERA experiment (oscillation project with emulsion-racking apparatus) at Italy’s Gran Sasso Laboratory astounded the scientific world by clocking neutrinos, a type of subatomic particle, that seemed to travel faster than the speed of light.
It was a feat that had been considered impossible, so the scientists asked colleagues to double-check the result. If the measurement panned out, it would call a century of physics into question, forcing scientists to rethink fundamental laws of the universe.
But on Friday, another experimental group at Gran Sasso, ICARUS (imaging cosmic and rare underground signal), reported that it had clocked seven neutrinos traveling the exact same underground path underground as the OPERA neutrinos ... and those neutrinos did not exceed the speed of light, after all.
The book isn’t completely closed on those faster-than-light neutrinos — at least three more experiments to test the OPERA result are still in the works at Gran Sasso, as well as separate efforts in Japan and the U.S. — but Friday’s announcement adds to a growing collection of evidence that something was amiss with the original claim.
Less than a month ago, for instance, reports emerged that there might have been a problem with communication between a GPS unit and a computer used to clock the tiny subatomic particles.
And long before that report emerged, most physicists said they figured the OPERA discovery would be overturned.
"If you have particles traveling faster than the speed of light, you can in principle go back in time. So you can be your own grandmother. As you can imagine, that causes some problems," Stephen Parke, a theoretical particle physicist at Fermilab in Batavia, Ill., told The Times in December.
"I'm fairly skeptical. I expect most people are," added Drexel University physicist Dave Goldberg.
For more on the neutrinos, check out this collection from the Los Angeles Times.
-- Eryn Brown
Photo: A scientist looks at OPERA equipment at the Gran Sasso laboratory in Italy in November. Credit: Alberto Pizzoli/AFP/Getty Images